Filter device

ABSTRACT

A filter device having a filter housing ( 2 ) and a filter element ( 15 ) accommodated therein, the element material ( 44 ) of which for filtering a liquid extends between two end caps ( 40, 42 ), at least one end cap ( 40 ) of which is mounted on an element receptacle ( 14 ), wherein a bearing ( 46, 54 ), providing more than one degree of freedom, is used to articulate the filter element ( 15 ) on the element receptacle ( 14 ) via its one end cap ( 40 ), characterized in that the bearing has a convex bearing surface ( 46 ) that is guided in a concave bearing surface ( 54 ) and in that the respective bearing surface ( 46, 54 ) is part of a shell ( 55   a,    55   b ), at least one ( 55   b ) of which has a passage ( 55   c ) for liquid media.

The invention relates to a filter device having a filter housing and a filter element accommodated therein, the element material of which for filtering a liquid extends between two end caps, at least one end cap of which is mounted on an element receptacle, wherein a bearing, providing more than one degree of freedom, is used to articulate the filter element on the element receptacle via its one end cap.

Filter devices are known in the prior art, see for instance DE 101 42 774 A1. In filter devices of this type in which, as in the case of the document referred to, element mounts are connected to the housing parts, such as housing connectors and/or connectors on the housing cover, in a form-fitting manner, the manufacture of filter housings and filter housing parts has to conform to extremely tight tolerances to ensure that the axes of the respective element mounts of the end caps are precisely aligned with the axes of the retaining elements, such as connectors, at the housing end and/or at the cover end. Manufacturing tolerances in the production of housings, in particular in the case of multi-part housing constructions having several adjacent housing parts, can lead to misalignments causing tensions in the filter element, resulting in malfunctions or even damage. In particular filter devices having long filter elements are affected by this problem, because even the smallest angular errors and positional deviations entail large misalignments at the opposite retaining element.

WO 02/076570 A1, WO 2007/003517 A2 and DE 10 2014 002 241 A1 specify further filtering devices.

In view of this problem, the invention addresses the problem of providing a filter device of the genus mentioned at the outset, which can be manufactured rationally and inexpensively and at the same time is characterized by safe operating behavior.

According to the invention, this problem is solved by a filter device having the features of claim 1 in its entirety.

According to the characterizing part of claim 1, an essential feature of the invention is that the bearing has a convex bearing surface that is guided in a concave bearing surface and that the respective bearing surface is part of a shell, at least one of which has a passage for liquid media.

A shell in terms of the invention and as defined in engineering mechanics is a planar supporting structure that has a doubly curved surface and that, in particular, can absorb loads both perpendicularly and in its plane. Shells make optimum use of their load-bearing capacity by distributing loads via membrane forces that are constant across the thickness of the shell, so that the shells have a high stiffness at a low weight.

A particular advantage of this design of bearing using shells is the passage being sealed off from the feed side of the filter device on the outside of the filter element.

It is further provided that the filter element is articulated to the element mount via its one end cap by means of a bearing providing more than one degree of freedom. This provides a compensation option for possibly occurring misalignment errors to enable a reduction of the narrow tolerance limits that have to be observed for manufacture and thus filter devices can be produced having long filter elements or having assembled filter housings in an operationally reliable manner and at favorable manufacturing costs.

Advantageously, the arrangement can be made in such a way that the bearing has at least one convex bearing surface guided in at least one concave bearing surface. In this way, a spherical bearing is formed, which forms a kind of ball joint between the respective end cap and the element receptacle to compensate for misalignments without tensioning.

The respective convex bearing surface may be part of the element receptacle, wherein the respective concave bearing surface is part of the one end cap. Because of the spherical shape of the element receptacle, the bearing surface of the filter element can easily be pushed onto the bearing surface of the element receptacle.

In preferred exemplary embodiments, the two bearing surfaces, in contact with each other in the manner of a plug-in or clamp connection, are spherical. The matching bulges thus form an axial safeguard for the filter element, the end cap of which is put onto the element receptacle.

In advantageous exemplary embodiments, the element receptacle is secured in the filter housing preferably by means of a screw connection, wherein the longitudinal axis of the filter element can in sections be swiveled out of the longitudinal axis of the element receptacle in all directions by a predeterminable swivel angle by means of the spherical bearing.

In particularly advantageous exemplary embodiments, a blocking device is provided, which delimits the maximum possible swivel-out angle of the filter element and which acts between the end cap of the filter element and the element mount and which is formed by these two. The limitation of the maximum inclination of the unit comprising the filter element and the element mount facilitates handling when inserting the filter element into the filter housing.

With particular advantage, the arrangement may be such that a further blocking device is provided which, when the element receptacle of the filter element is screwed onto a housing mount, arranged inside the filter housing, prevents the swivel motion out of the basic position, in which the longitudinal axes of the one end cap and the assigned element receptacle are congruent with each other, and that, when the element receptacle is secured to the housing mount and in the event of further rotational motion of the one end cap relative to the element receptacle, preferably in the screw-on direction, the further blocking device permits the swivel motion from the basic position. When the further blocking device is in the active state, for the installation process of the filter element in the filter housing the filter element together with the element receptacle is available as a rigid unit having aligned axes. This setup forms a particularly effective assembly aid in the assembly process, in which the element receptacle has to be engaged with the thread of the housing mount, which is difficult to access inside the housing. Because the blocking device is deactivated in the course of screwing-on the filter element, it is simultaneously ensured that the spherical bearing for compensating possible misalignments is effective when the installation screw process is completed.

In advantageous exemplary embodiments, the further end cap of the filter element is secured to a further housing mount inside the filter housing, wherein the further housing mount is preferably part of a housing cover that is secured to a filter head as part of the filter housing, in particular by means of at least one screw connection. The further housing mount may be formed by a connector of the housing cover, which engages with an opening of the assigned end cap of the filter element. The connector may form a closure of this end cap or a fluid path leading from the filter head to the interior of the filter element.

Advantageously, the one housing mount may have at least one spring-loaded bypass valve, which, in its open position, while at least partially bypassing the filter element, releases the fluid path from the inside of the filter housing to its outlet. The fluid path may be routed via a cavity formed by the one end cap, which is sealed to the housing mount, wherein said cavity contains a screen mesh through which the fluid flows when the bypass valve is open.

According to patent claim 11, the subject matter of the invention is also a filter element, which is provided in particular for a filter device according to any one of claims 1 to 10.

The invention is explained in detail below with reference to an exemplary embodiment shown in the drawing. In the Figures:

FIG. 1 shows a perspective oblique view, sectioned in a central and vertical sectional plane, of the exemplary embodiment of the filter device according to the invention;

FIG. 2 shows an enlarged perspective oblique view, sectioned in a central vertical plane, of the one end cap and its assigned element receptacle of the filter element of the exemplary embodiment;

FIG. 3 shows a perspective oblique view, further enlarged compared to FIG. 2, showing the area of two blocking devices of the exemplary embodiment, both shown in the blocking position; and

FIG. 4 shows a representation corresponding to FIG. 3, wherein one of the blocking devices is shown in the releasing position.

With reference to the drawings, the invention is explained by way of example of a so-called in-tank filter device, which has a filter housing 2 in the form of a tubular body open at its lower end 4. The invention is equally advantageously implemented in a filter device which provides a filter housing in the form of a filter bowl closed at the bottom. Near the lower end 4, a housing mount 6 is secured to the inside of the tubular body of the filter housing 2. The housing mount 6 is formed by a two-part annular body having a coaxial internal passage 8. At the top part 10, the passage 8 continues with an upwardly projecting threaded connector 12, to the male thread of which the female thread of a threaded ring 26 of an element receptacle 14 can be screwed for the support a filter element 15. The female thread can be used to detachably secure the element receptacle 14 in the filter housing 2. In the lower part 16 of the housing mount 6 valve chambers 18, arranged distributed around the outside of the central passage 8, for bypass valves are formed, which have fluid passages from an upper circular ring surface 20 of the upper part 10 to fluid passages 22 on the lower part 16. The fluid passages 22 are normally closed by spring-loaded closing elements 24.

FIG. 1 shows the filter element 15 in the installed functional position, in which the threaded ring 26, projecting coaxially downward from the element receptacle 14, is screwed to the threaded connector 12 of the housing mount 6, wherein for the tightened screw connection, the end 28 (see FIG. 2) of the threaded ring 26 contacts the circular ring surface 20 of the upper part 10. As can be seen most clearly from FIG. 2, the threaded ring 26 extends from the underside of a planar annular top surface 30, extending in a radial plane, of the element receptacle 14, wherein from the outer periphery of said top surface 30 a bell-like sleeve 32 extends toward the threaded ring 26. The sleeve 32 has wall openings 34 and delimits an annular space 36 between itself and the threaded ring 26. In the screwed functional position, shown in FIG. 1, the lower annular edge 38 of the sleeve 32, like the end 28 of the threaded ring 26, is in contact with the circular ring surface 20 of the upper part 10 of the housing mount 6.

In a conventional manner, the filter element 15 has an element material 44, extending between the end caps 40 and 42, in the form of a hollow cylinder. The one end cap 40, shown at the bottom in FIG. 1, of the end caps 40, 42 is supported on the element receptacle 14. To form the bearing, the element receptacle 14, see FIGS. 2 to 4, has a tubular body 48 projecting coaxially upwards from the cover surface 30, wherein the radially outer wall of said tubular body 48 forms a bearing surface 46 in the form of a convexly curved annular surface. The end cap 40 has, starting from the radially inner edge of a flat contact surface 50 for the front end of the element material 44, an upwardly and downwardly projecting tubular body 52, the radially inner wall of which forms the second bearing surface 54 in the form of a concavely curved annular surface.

The figures, see in particular FIG. 2, show the bearing state, in which the tubular body 52 of the end cap 40 is fitted onto the tubular body 48 of the element receptacle 14, wherein elastic flexibility, in particular of the tubular body 48 free-standing on the cover surface 30, can be used to latch the bearing to the adjoining bearing surfaces 46, 54. The contact of the convex bearing surface 46 with the concave bearing surface 54 forms a spherical bearing in the manner of a ball joint between the end cap 40 and the element receptacle 14. The respective bearing surface 46, 54 is constituent part of membrane-like shell 55 a, 55 b, at least one 55 b of which has a passage 55 c for fluid, which is connected to a cavity 55 d in the filter element in a fluid-conveying manner. The enclosure for the element material 44, contacting on the contacting surface 50 of the end cap 40, is formed on the radial inside by the tubular body 52 and on the radial outside by a sleeve surface 56, which widens upward in the radial direction to form a shell 58 surrounding the end part of the element material 44 at a radial distance.

The spherical bearing formed permits a deflection of the longitudinal axes of the element receptacle 14 relative to the filter element 15 from the aligned basic position as shown in FIGS. 1 and 2. In this aligned position, the lower edge 61 of the tubular body 52 of the end cap 40 is spaced apart from the top surface 30 of the element receptacle 14. In contrast, FIGS. 3 and 4 show a deflected state, or more precisely, the maximum possible deflection at which the lower edge 60 of the annular body 52 contacts the cover surface 30, forming a stop, of the element receptacle 14. This forms a blocking device delimiting the maximum deflection.

FIGS. 2 to 4 show closer details of a further blocking device formed by formations on the upper end edge 60 of the tubular body 48 of the element receptacle 14 and the upper end edge 62 of the tubular body 52 of the end cap 40. As shown, this blocking device has a locking block 64, projecting radially inwards from the inside of the end edge 62 of the tubular body 52 and having the form of a short rectangular rib. At the end edge 60 of the other, inner tubular body 48 a recess 66 is formed, which extends in steps 68 and 70 (see in particular FIGS. 3 and 4) across one circumferential section of the tubular body 48 each. In the first step 68, the recess 66 forms an axial deepening of the end edge 62 corresponding to the axial thickness of the locking block 64 and is limited in the circumferential direction by a projection 72, protruding slightly from the step surface, to a circumferential length only slightly greater than the length of the locking block 64 measured in the circumferential direction, see FIG. 3. The second step 70 adjoins the first step 68 at the projection 72, wherein said second step results in the end edge 62 being further recessed in the axial direction and has a greater circumferential length than the first step 68.

In this arrangement, the function of this further blocking device is as follows: FIGS. 2 and 3 show the basic position in which the axis of filter element 15 together with the end cap 40 is aligned with the longitudinal axis of the element receptacle 14. The locking body 64 of the end cap 40 is located in the first step 68 of the recess 66 of the tubular body 48 of the element receptacle 14. Because the axial extension of the first step 68 corresponds to the thickness of the locking block 64 measured in the axial direction, the spherical bearing is blocked against deflection. At the same time, the projection 72 impedes the sliding motion of the locking block 64 in the circumferential direction, so that in this basic position a rotational interlock is formed between the filter element 15 and the element receptacle 14. In the basic position, therefore, during the assembly process for installing the filter element 15 in the filter housing 2, the filter element 15 together with the element receptacle 14, forming a rigid unit therewith, can be conveniently and securely placed against the threaded ring 26 of the housing mount 6 and screwed tight by the rotary catch formed. When the screw connection is formed, the rotational interlock, formed by the projection 72, can be overcome by further rotation such that the locking block 64 overruns the projection 72 and enters the free space formed by the second step 70 of the recess 66. Due to the increased axial depth of the step 70, the locking block 64 is no longer axially supported, permitting the spherical bearing to be released and within the limits formed by the first blocking device to be deflected to compensate for misalignment.

The other, upper end cap 42, in the exemplary embodiment shown, see FIG. 1, engages with an element receptacle formed by a connector 74 that engages with the central opening 76 of the end cap 42. Instead of this form-fit engagement, a spherical bearing of the type shown on the lower end cap 40 can also be provided between the upper end cap 42 and the element receptacle concerned. The connector 74, provided in the example shown, is constituent part of a housing cover 78 that is removably secured to a filter head 80 using screw connections 85, wherein said filter head 80 has an unfiltered input 82 and, as per usual for in-tank filter devices, is attached to an opening in a tank wall not shown. In the functional position shown in FIG. 1, the end 28 of the threaded ring 26 and the end edge 38 of the element receptacle 14 are in close contact with the circular ring surface 20 of the housing mount 6. For the unfiltered matter gaining access to the bypass valves in the lower part 16 of the housing mount 6, the annular space 36 located inside the sleeve 32 forms an inflow space into which unfiltered matter enters via the wall openings 34. Openings 84 are provided in the circular ring surface 20, forming the bottom of this annular space 36, wherein said openings 84 are normally closed by the closing bodies 24 of the respective bypass valve. Injected screen grids may be provided at the wall openings 34 of the sleeve 32 to provide filtration of the flow of unfiltered matter when a bypass valve is opened by pressure. In an embodiment not shown, it is also possible to relocate the spherical bearing presented from the lower to the upper element end, or to provide such a bearing at both element ends. 

1. A filter device having a filter housing (2) and a filter element (15) accommodated therein, the element material (44) of which for filtering a liquid extends between two end caps (40, 42), at least one end cap (40) of which is mounted on an element receptacle (14), wherein a bearing (46, 54), providing more than one degree of freedom, is used to articulate the filter element (15) on the element receptacle (14) via its one end cap (40), characterized in that the bearing has a convex bearing surface (46) that is guided in a concave bearing surface (54) and in that the respective bearing surface (46, 54) is part of a shell (55 a, 55 b), at least one (55 b) of which has a passage (55 c) for liquid media.
 2. The filter device according to claim 1, characterized in that the bearing has at least one convex bearing surface (46) guided in at least one concave bearing surface (54).
 3. The filter device according to claim 1, characterized in that the respective convex bearing surface (46) is part of the element receptacle (14) and the respective concave bearing surface (54) is part of the one end cap (40).
 4. The filter device according to claim 1, characterized in that the two bearing surfaces (46, 54), in contact with each other in the manner of a plug-in or clamp connection, are spherical.
 5. The filter device according to claim 1, characterized in that the element receptacle (14) is secured in the filter housing (2) preferably by means of a screw connection (12, 26).
 6. The filter device according to claim 1, characterized in that the longitudinal axis of the filter element (15) can in sections be swiveled out of the longitudinal axis of the element receptacle (14) in all directions by a predeterminable swivel angle by means of the spherical bearing (46, 54).
 7. The filter device according to claim 1, characterized in that a blocking device (30, 61), delimiting the maximum possible deflection angle of the filter element (15), is provided, wherein said blocking device (30, 61) acts between the end cap (40) of the filter element (15) and the element mount (14) and is formed by these two.
 8. The filter device according to claim 1, characterized in that a further blocking device (64, 66, 68, 70) is provided, which, when the element receptacle (14) of the filter element (15) is screwed to a housing mount (6), arranged inside the filter housing (2), prevents the swivel motion out of a basic position, in which the longitudinal axes of the one end cap (40) and the assigned element receptacle (14) are congruent with each other, and in that, when the element receptacle (14) is secured to the housing mount (6) and in the event of further rotational motion of the one end cap (40) relative to the element receptacle (14), preferably in the screw-on direction, the further blocking device (64, 66, 68, 70) permits the swivel motion from the basic position.
 9. The filter device according to claim 1, characterized in that the further end cap (42) of the filter element (15) is secured to a further housing mount (74) inside the filter housing (2), and in that the further housing mount (74) is preferably part of a housing cover (78) that is secured to a filter head (80) as part of the filter housing (2), in particular by means of at least one screw connection (84).
 10. The filter device according to claim 1, characterized in that the one housing mount (6) has at least one spring-loaded bypass valve (24), which, in its open position, while at least partially bypassing the filter element (15), releases the fluid path from the inside of the filter housing (2) to its outlet (4).
 11. The filter element, in particular for a filter device according to claim 1, the element material (44) of which is arranged between two end caps (40, 42) while delimiting an inner cavity (55 d), characterized in that at least one of the end caps (40) has a shell-like, preferably spherically shaped, bearing surface (46), which comprises a passage (55 c) for liquid media, wherein said passage (55 c) is connected to the cavity (55 d) in a fluid-conveying manner. 